With development of mobile communications technologies and massive deployment of a 3rd generation mobile communications technology (3G) network, a high-rate and high-bandwidth communications service greatly improves user experience. However, more challenges are brought to operation of communications services although massive popularization of a smartphone injects new vitality into the communications services. Because a limited throughput of a 3G network cannot meet such heavy traffic, a current network of an operator has been faced with great pressure, and even massive deployment of a Long Term Evolution (LTE) system in future can meet only some demands. Due to its flexible deployment, low cost, and broadband transmission provided for a user, a micro cell has become a key direction in which an LTE network evolves. A micro cell node of the micro cell may be a micro cell node of a small cell, an indoor base station (Femto base station), a local wireless access point (AP), or a low power node (LPN).
In consideration of reducing costs of an access point and simplifying a function of the micro cell node, the micro cell node has no Radio Resource Control (RRC) protocol function layer or has only a simple RRC function layer, that is, the micro cell node cannot generate or parse a dedicated RRC message of a user equipment (UE), has no radio resource management function, or cannot generate all cell common control information. However, the function of the micro cell node is that the micro cell node independently allows access of a backward compatible UE, thereby implementing a necessary function for UE mobility. If the micro cell node does not have the function, access of the backward compatible UE is unavailable and a service cannot be provided for the backward compatible UE. The backward compatible UE refers to a UE in an earlier version. To access a cell, the backward compatible UE has the following requirements for a base station: needing system information, needing to receive a paging message, and needing to establish a relationship with the base station by using an RRC message.